Phosphatidic acid is a key intermediate in the metabolism of brain lipids. The major objective of the proposed research is to establish the formation of phosphatidic acid in brain by the reduction and subsequent acylation of acyl dihydroxyacetone phosphate (acyl DHAP), a newly discovered lipid, and to compare different pathways for the biosynthesis of phosphatidic acid. Preliminary findings show that the pathway of phosphatidate formation via acyl DHAP is present in brain. Acyl DHAP, formed by the acylation of DHAP by acyl CoA, is also shown to be the precursor of lipids containing ether bond. These lipids are widespread in nature and are found in relatively large amounts in brain. Long chain alcohol in the presence of ATP and Mg ions substitute the acyl group in acyl DHAP to form O-alkyl DHAP which is reduced (by NADPH) and then acylated to form the ether analogue of phosphatidic acid. The future work will be directed in elucidating the mechanism of this novel biosynthetic reaction and the role of acyl DHAP in overall brain lipid metabolism.